Hour-long delays are expected for passengers using the London to Scotland rail route following three separate incidents on the West Coast main line.
Services were disrupted earlier by two overhead cable problems, one north of Rugby in the West Midlands, the other at Bletchley in Buckinghamshire.
A cracked rail on the recently upgraded £9bn line between Coventry and Birmingham has caused further delays.
Virgin trains were unable to call at stations between Rugby and Stafford.
Network Rail said it was doing all it could to keep the line open while it carried out essential repairs and expected to have all services running normally by the afternoon.
"We share our customers' frustrations at the problems they have had"
A new timetable was introduced for West Coast services on 14 December following major upgrades.
"This is a massive piece of infrastructure and it doesn't mean however that it isn't going to go wrong. We are working on there to fix it right now," Network Rail said.
For safety reasons 20mph (32kph) speed restrictions were in place for trains using the Birmingham to Coventry line.
Network Rail said the average train speed along this stretch was normally between 80-125 mph. (128-201kmh)
Trains were also being diverted away from Coventry and Birmingham International stations.
National Rail Enquiries said replacement services would operate between Coventry and Birmingham until 1300 GMT on Tuesday.
Fatal crash
The London Midland train company was only able to run services between Northampton and London and a replacement bus service was operating between Rugby and Nuneaton.
Services were also disrupted last week after a light plane crashed close to the line near Stafford, leaving three people dead.
An overhead cabling problem at Watford in Hertfordshire meant services were then affected on Sunday and Monday.
Virgin Trains said: "We share our customers' frustrations at the problems they have had."
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